Footprints are now stored on its own directory, as we consider .fpd files [1]
not as footprints by themselves, but as wizard description files,
whose output may be manually modified in order to fix things that aren't
accounted for under fped.
This way, layouters can modify .mod files to suit their needs without
worrying about breaking .fpd <-> .mod relationship, as we consider fped a
tool to draw kicad version controlled footprints.
[1] As per conversation hold on IRC between ceene and Joerg
https://irclog.whitequark.org/neo900/2017-07-02#19689118